leds: add driver for LM3530 ALS

Simple backlight driver for National Semiconductor LM3530.  Presently only
manual mode is supported, PWM and ALS support to be added.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 6f190f4..9bec869 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -34,6 +34,16 @@
 	  This option enables support for LEDs driven using outputs
 	  of the dedicated PWM controller found on newer Atmel SOCs.
 
+config LEDS_LM3530
+	tristate "LCD Backlight driver for LM3530"
+	depends on LEDS_CLASS
+	depends on I2C
+	help
+	  This option enables support for the LCD backlight using
+	  LM3530 ambient light sensor chip. This ALS chip can be
+	  controlled manually or using PWM input or using ambient
+	  light automatically.
+
 config LEDS_LOCOMO
 	tristate "LED Support for Locomo device"
 	depends on LEDS_CLASS